#include "sha256.h"
#include <stdint.h>
#include <stdbool.h>
#include <stddef.h>
#include <string.h>
#include "bswap.h"

#undef RND

#define STATE_NUM 8
#define SHA256_BLKSIZE 64

typedef struct {
    uint32_t state[STATE_NUM];
    uint64_t size;
    uint32_t offset;
    uint8_t buf[SHA256_BLKSIZE];
} Sha256Type;

static void SHA256_Init(Sha256Type *ctx)
{
    ctx->offset = 0;
    ctx->size = 0;
    ctx->state[0] = 0x6a09e667ul;
    ctx->state[1] = 0xbb67ae85ul;
    ctx->state[2] = 0x3c6ef372ul;
    ctx->state[3] = 0xa54ff53aul;
    ctx->state[4] = 0x510e527ful;
    ctx->state[5] = 0x9b05688cul;
    ctx->state[6] = 0x1f83d9abul;
    ctx->state[7] = 0x5be0cd19ul;
}

static inline uint32_t ror(uint32_t x, unsigned n)
{
    return (x >> n) | (x << (32 - n));
}

static inline uint32_t ch(uint32_t x, uint32_t y, uint32_t z)
{
    return z ^ (x & (y ^ z));
}

static inline uint32_t maj(uint32_t x, uint32_t y, uint32_t z)
{
    return ((x | y) & z) | (x & y);
}

static inline uint32_t sigma0(uint32_t x)
{
    return ror(x, 2) ^ ror(x, 13) ^ ror(x, 22);
}

static inline uint32_t sigma1(uint32_t x)
{
    return ror(x, 6) ^ ror(x, 11) ^ ror(x, 25);
}

static inline uint32_t gamma0(uint32_t x)
{
    return ror(x, 7) ^ ror(x, 18) ^ (x >> 3);
}

static inline uint32_t gamma1(uint32_t x)
{
    return ror(x, 17) ^ ror(x, 19) ^ (x >> 10);
}

static void SHA256_Transform(Sha256Type *ctx, const unsigned char *buf)
{
    uint32_t S[8], W[64], t0, t1;
    int i;

    /* copy state into S */
    for (i = 0; i < 8; i++) {
        S[i] = ctx->state[i];
    }

    /* copy the state into 512-bits into W[0..15] */
    for (i = 0; i < 16; i++, buf += sizeof(uint32_t)) {
        W[i] = get_be32(buf);
    }

    /* fill W[16..63] */
    for (i = 16; i < 64; i++) {
        W[i] = gamma1(W[i - 2]) + W[i - 7] + gamma0(W[i - 15]) + W[i - 16];
    }

#define RND(a, b, c, d, e, f, g, h, i, ki)        \
    t0 = h + sigma1(e) + ch(e, f, g) + ki + W[i]; \
    t1 = sigma0(a) + maj(a, b, c);                \
    d += t0;                                      \
    h = t0 + t1;

    RND(S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7], 0, 0x428a2f98);
    RND(S[7], S[0], S[1], S[2], S[3], S[4], S[5], S[6], 1, 0x71374491);
    RND(S[6], S[7], S[0], S[1], S[2], S[3], S[4], S[5], 2, 0xb5c0fbcf);
    RND(S[5], S[6], S[7], S[0], S[1], S[2], S[3], S[4], 3, 0xe9b5dba5);
    RND(S[4], S[5], S[6], S[7], S[0], S[1], S[2], S[3], 4, 0x3956c25b);
    RND(S[3], S[4], S[5], S[6], S[7], S[0], S[1], S[2], 5, 0x59f111f1);
    RND(S[2], S[3], S[4], S[5], S[6], S[7], S[0], S[1], 6, 0x923f82a4);
    RND(S[1], S[2], S[3], S[4], S[5], S[6], S[7], S[0], 7, 0xab1c5ed5);
    RND(S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7], 8, 0xd807aa98);
    RND(S[7], S[0], S[1], S[2], S[3], S[4], S[5], S[6], 9, 0x12835b01);
    RND(S[6], S[7], S[0], S[1], S[2], S[3], S[4], S[5], 10, 0x243185be);
    RND(S[5], S[6], S[7], S[0], S[1], S[2], S[3], S[4], 11, 0x550c7dc3);
    RND(S[4], S[5], S[6], S[7], S[0], S[1], S[2], S[3], 12, 0x72be5d74);
    RND(S[3], S[4], S[5], S[6], S[7], S[0], S[1], S[2], 13, 0x80deb1fe);
    RND(S[2], S[3], S[4], S[5], S[6], S[7], S[0], S[1], 14, 0x9bdc06a7);
    RND(S[1], S[2], S[3], S[4], S[5], S[6], S[7], S[0], 15, 0xc19bf174);
    RND(S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7], 16, 0xe49b69c1);
    RND(S[7], S[0], S[1], S[2], S[3], S[4], S[5], S[6], 17, 0xefbe4786);
    RND(S[6], S[7], S[0], S[1], S[2], S[3], S[4], S[5], 18, 0x0fc19dc6);
    RND(S[5], S[6], S[7], S[0], S[1], S[2], S[3], S[4], 19, 0x240ca1cc);
    RND(S[4], S[5], S[6], S[7], S[0], S[1], S[2], S[3], 20, 0x2de92c6f);
    RND(S[3], S[4], S[5], S[6], S[7], S[0], S[1], S[2], 21, 0x4a7484aa);
    RND(S[2], S[3], S[4], S[5], S[6], S[7], S[0], S[1], 22, 0x5cb0a9dc);
    RND(S[1], S[2], S[3], S[4], S[5], S[6], S[7], S[0], 23, 0x76f988da);
    RND(S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7], 24, 0x983e5152);
    RND(S[7], S[0], S[1], S[2], S[3], S[4], S[5], S[6], 25, 0xa831c66d);
    RND(S[6], S[7], S[0], S[1], S[2], S[3], S[4], S[5], 26, 0xb00327c8);
    RND(S[5], S[6], S[7], S[0], S[1], S[2], S[3], S[4], 27, 0xbf597fc7);
    RND(S[4], S[5], S[6], S[7], S[0], S[1], S[2], S[3], 28, 0xc6e00bf3);
    RND(S[3], S[4], S[5], S[6], S[7], S[0], S[1], S[2], 29, 0xd5a79147);
    RND(S[2], S[3], S[4], S[5], S[6], S[7], S[0], S[1], 30, 0x06ca6351);
    RND(S[1], S[2], S[3], S[4], S[5], S[6], S[7], S[0], 31, 0x14292967);
    RND(S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7], 32, 0x27b70a85);
    RND(S[7], S[0], S[1], S[2], S[3], S[4], S[5], S[6], 33, 0x2e1b2138);
    RND(S[6], S[7], S[0], S[1], S[2], S[3], S[4], S[5], 34, 0x4d2c6dfc);
    RND(S[5], S[6], S[7], S[0], S[1], S[2], S[3], S[4], 35, 0x53380d13);
    RND(S[4], S[5], S[6], S[7], S[0], S[1], S[2], S[3], 36, 0x650a7354);
    RND(S[3], S[4], S[5], S[6], S[7], S[0], S[1], S[2], 37, 0x766a0abb);
    RND(S[2], S[3], S[4], S[5], S[6], S[7], S[0], S[1], 38, 0x81c2c92e);
    RND(S[1], S[2], S[3], S[4], S[5], S[6], S[7], S[0], 39, 0x92722c85);
    RND(S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7], 40, 0xa2bfe8a1);
    RND(S[7], S[0], S[1], S[2], S[3], S[4], S[5], S[6], 41, 0xa81a664b);
    RND(S[6], S[7], S[0], S[1], S[2], S[3], S[4], S[5], 42, 0xc24b8b70);
    RND(S[5], S[6], S[7], S[0], S[1], S[2], S[3], S[4], 43, 0xc76c51a3);
    RND(S[4], S[5], S[6], S[7], S[0], S[1], S[2], S[3], 44, 0xd192e819);
    RND(S[3], S[4], S[5], S[6], S[7], S[0], S[1], S[2], 45, 0xd6990624);
    RND(S[2], S[3], S[4], S[5], S[6], S[7], S[0], S[1], 46, 0xf40e3585);
    RND(S[1], S[2], S[3], S[4], S[5], S[6], S[7], S[0], 47, 0x106aa070);
    RND(S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7], 48, 0x19a4c116);
    RND(S[7], S[0], S[1], S[2], S[3], S[4], S[5], S[6], 49, 0x1e376c08);
    RND(S[6], S[7], S[0], S[1], S[2], S[3], S[4], S[5], 50, 0x2748774c);
    RND(S[5], S[6], S[7], S[0], S[1], S[2], S[3], S[4], 51, 0x34b0bcb5);
    RND(S[4], S[5], S[6], S[7], S[0], S[1], S[2], S[3], 52, 0x391c0cb3);
    RND(S[3], S[4], S[5], S[6], S[7], S[0], S[1], S[2], 53, 0x4ed8aa4a);
    RND(S[2], S[3], S[4], S[5], S[6], S[7], S[0], S[1], 54, 0x5b9cca4f);
    RND(S[1], S[2], S[3], S[4], S[5], S[6], S[7], S[0], 55, 0x682e6ff3);
    RND(S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7], 56, 0x748f82ee);
    RND(S[7], S[0], S[1], S[2], S[3], S[4], S[5], S[6], 57, 0x78a5636f);
    RND(S[6], S[7], S[0], S[1], S[2], S[3], S[4], S[5], 58, 0x84c87814);
    RND(S[5], S[6], S[7], S[0], S[1], S[2], S[3], S[4], 59, 0x8cc70208);
    RND(S[4], S[5], S[6], S[7], S[0], S[1], S[2], S[3], 60, 0x90befffa);
    RND(S[3], S[4], S[5], S[6], S[7], S[0], S[1], S[2], 61, 0xa4506ceb);
    RND(S[2], S[3], S[4], S[5], S[6], S[7], S[0], S[1], 62, 0xbef9a3f7);
    RND(S[1], S[2], S[3], S[4], S[5], S[6], S[7], S[0], 63, 0xc67178f2);

    for (i = 0; i < 8; i++) {
        ctx->state[i] += S[i];
    }
}

static void SHA256_Update(Sha256Type *ctx, const void *data, size_t len)
{
    unsigned int len_buf = ctx->size & 63;

    ctx->size += len;

    /* Read the data into buf and process blocks as they get full */
    if (len_buf) {
        unsigned int left = 64 - len_buf;
        if (len < left)
            left = len;
        memcpy(len_buf + ctx->buf, data, left);
        len_buf = (len_buf + left) & 63;
        len -= left;
        data = ((const char *)data + left);
        if (len_buf)
            return;
        SHA256_Transform(ctx, ctx->buf);
    }
    while (len >= 64) {
        SHA256_Transform(ctx, data);
        data = ((const char *)data + 64);
        len -= 64;
    }
    if (len) {
        memcpy(ctx->buf, data, len);
    }
}

static void SHA256_Final(Sha256Type *ctx, unsigned char *digest)
{
    static const unsigned char pad[64] = { 0x80 };
    unsigned int padlen[2];
    int i;

    /* Pad with a binary 1 (ie 0x80), then zeroes, then length */
    padlen[0] = htonl((uint32_t)(ctx->size >> 29));
    padlen[1] = htonl((uint32_t)(ctx->size << 3));

    i = ctx->size & 63;
    SHA256_Update(ctx, pad, 1 + (63 & (55 - i)));
    SHA256_Update(ctx, padlen, 8);

    /* copy output */
    for (i = 0; i < 8; i++, digest += sizeof(uint32_t)) {
        put_be32(digest, ctx->state[i]);
    }
}

bool CalcHash256Value(uint8_t *data, size_t len, uint8_t *outHash)
{
    Sha256Type tmp = { 0 };

    if (data == NULL || len == 0x00 || outHash == NULL) {
        return false;
    }

    SHA256_Init(&tmp);
    SHA256_Update(&tmp, data, len);
    SHA256_Final(&tmp, outHash);

    return true;
}